An emerging technology, known by various names such as in-line flocculation, polymer modified tailings deposition or more commercially as enhanced tailings disposal (ETD), is the subject of growing interest from mining operations. Business drivers for the mine tailings facility owners can include a variety of site-specific, material-dependant operational challenges, as well as more general desires to improve efficiency at tailings storage facilities (TSFs). Polymers can modify the behaviour of tailings in a variety of ways; one of these is through rheological adjustment. This can often result in a steepened beach which, with careful design and use of natural or man-made landforms, can result in the potential for significant reduction in the volume of initial embankment construction material. These opportunities are the subject of a number of ongoing large-scale operational trials that are likely to become the topic of future papers. Other material behavioural changes are inextricably linked with the technology. These include reduced segregation, improved water release, less long-term settlement, and improving permeability and subsequent consolidation behaviour. Thorough understanding of these improvements can allow for appropriate design and operational management, which can then allow the operator leverage to improve long-term operational performance. This paper describes some scoping-level testing that focused on potential time-related opportunities that may lead to more efficient tailings management. Subject to site-specific constraints, there may be a costeffective opportunity to defer future capital expenditure required for construction of a subsequent facility, or construction of the next raise of the embankments. Increased consolidation rates may also lead to improved trafficability and thus more efficient rehabilitation. Whilst not going into specific detail concerning operational or construction costs, this paper presents high-level results of testing and consolidation modelling, demonstrating a combination of opportunities for improved tailings performance through the implementation of the following:  Accelerating and increasing overall water release.  Improving the rate of consolidation.  Reducing the rate of rise.  Reducing the amount of post depositional settlement. The implications of the data and modelling are discussed in the context of potential business opportunities, which can be broadly described as the 'time value of volume'.

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Estimation of e0 is an important parameter when gaining information on the behaviour of tailings after polymer treatment, as it is a critical input when trying to predict field scale consolidation behaviour with the use of modelling techniques. Many laboratory experiments were undertaken to determine the uncertainty ranges in estimated values of e0, varying both the starting height of the tailings, starting solids concentration, with and without polymer treatment in beakers, graduated cylinders and custom built 10 L columns with evenly spaced sample ports. 95% confidence intervals range from 0.047~0.14 for e0 values in the range of 3.5~4.5 highlighting the robustness of the experimental methods and the viability of using experimentally determined e0 as an input for consolidation modelling. Sample ageing and solids concentration were found to have an impact on compressibility and permeability behaviour of the suspensions, however it is likely that the variability relates to an increased polymer demand rather than variation of the consolidation behaviour of the material itself. Observations made using varying starting height of the tailings suggest that this factor has no impact on void ratio, however increasing the internal diameter of the vessels used to measure the void ratio at varying effective stress suggests that wall effects may be a factor for slurries with high solids densities.

Thickening of tailings material produced in the mining, chemical, water supply and sanitation industries started in 1905 in conventional thickeners that were used well into the 1960s. The development of water soluble polymer flocculants in mineral processing is necessary to make thickening, clarification and tailings treatment processes effective. BASF has a range of polymers that are used for these processes in a variety of industries. Ever increasing tonnages of low grade ore or the treatment of more challenging substrates have highlighted limitations in the conventional systems used for hydration and dissolution of polymers that make them ready for use. When these systems are pushed to nameplate capacity, field observations indicate that plant availability can be impacted with symptoms such as foaming, powder blockages and gelatinous masses limiting any improvements. Where significant process streams require treatment with a polymer, arguably the most economical product form is a powder, which is then pneumatically transferred into a storage silo. Hydration and dissolution of the polymer before use is typically conducted in batch process where separate powder storage, hydration tank and ageing tanks are used. These conventional systems, although scalable to an extent, have limitations and require large footprints, services and civils to allow the polymer to be effective. For example, typical systems of this design type are used where polymer dissolution rates or equipment duty required is < 500 kg/hr. These systems are typically made to order with lead times on detailed design, engineering and fabrication of up to six months. Limitations on hydration systems have been largely factored around powder handling, initial wetting out of the polymer while ensuring its integrity and maintaining the performance of the polymer. A novel approach was taken to designing a modular, continuous polymer system capable of producing 1600 kg/hr of dry polymer into concentrated solution with minimal civil requirements that was delivered within 6~8 months and has now been operating in a hostile environment for over two years. This paper focuses on design considerations for a Modular Continuous Polymer System (CPS).